Miscalculation
by Elbowless-Rubber-Duck
Summary: AU where Tom Riddle is a student in the 90s. Hermione Granger did not hate the Head Boy. She was just competitive, and Tom Riddle was the only student in the entire school who consistently edged her out of the top spot by a single point. Every. Damn. Year.


Hermione Granger did not hate the Head Boy. She was just competitive, and Tom Riddle was the only student in the entire school who consistently edged her out of the top spot by a single point. Every damn year. She knew— _she knew_ —that Professor Slughorn favored his Slytherins and Tom in particular, and that was really the only reason she and Tom weren't tied for first place. And while some days she thought that maybe Tom might've deserved that extra point—his potions were flawless—she also knew that he gifted Professor Slughorn crystallized pineapple every Slug Club meeting.

And wouldn't you know, crystallized pineapple happened to be a favorite of the potions professor.

But aside from vaguely sucking up to professors—which Hermione was practically guilty of herself—Riddle had a spotless reputation. Slytherins were notoriously tight-lipped, and Riddle was so obviously their king, but even so, something should have slipped through. There was not one single rumor of him being intoxicated despite the fact that Hermione had seen him drinking firewhiskey on numerous occasions at Professor Slughorn's insistence. No drunken mishaps. No wild parties in the dungeons.

He wasn't a bully either. Which made sense to some extent, because Hermione was sure that even with Riddle's perfect grades, Headmaster Dumbledore wouldn't have let him become Head Boy if he was some kind of delinquent. But again, Riddle hadn't had even one detention. He'd never been so much as rumored as to have said something insensitive or mean.

Riddle didn't have a single messy break-up to his name either, though not for lack of partners. He was handsome and polite and took care in his self-image, so it was no surprise that he had a great many admirers. But nobody ever dated Tom Riddle for very long, and Hermione was nearly positive that was Riddle's doing, so the logical conclusion was that he should have had at least a few scorned lovers.

No such luck.

Hermione didn't have any reason to think he was anything other than the perfect Head Boy that everyone else seemed content to adore. It was just a gut feeling, a little twist of her stomach every time the boy smiled that had nothing to do with butterflies. There was just something…off about Riddle, and that was all Hermione knew.

If the tall, dark-haired boy was at all aware of her suspicions, he certainly didn't show it. Even now as they were doing rounds, he was nothing but amicable. Hermione might've called him chatty, even.

"And Professor Flitwick has asked us to help with the Halloween decorations again this year," Riddle said as they rounded the corner of the fourth floor. "I'm afraid neither Belby nor Flint have much of a talent for such things—you remember the disaster last Yule, I'm sure—so I'm afraid we'll have to spear-head it ourselves. If I recall correctly, you're quite gifted at charms."

Riddle flashed her one of his signature, charming smiles. Or, as Lavender Brown had so _delightfully_ put it, "the panty-dropping grin." Hermione supposed it was aesthetically pleasing in an objective sort of way, but she didn't think it suited him. It was too wide, toothy, like he'd plucked it from someone else's face and made it his own.

 _My parents would love to get a look at his teeth,_ she thought absently, forcing her own lips into a small, lopsided smile.

"I'm adept enough for the task at hand," she replied dryly. "Though it's not exactly hard to beat Flint and Belby's work. Honestly, it was a terrible enough idea to transfigure devil's snare into mistletoe, but they could have at least asked someone competent to do it. Maybe then it wouldn't have tried to strangle the couples."

Riddle hummed in agreement. "Between the two of us, I'm sure we'll avoid any such mishaps."

Hermione forced her smile to stay in place. To anyone else, it may have sounded like a compliment of her abilities—after all, who wouldn't want to be praised by the magical prodigy himself—but Hermione thought there was something else in his voice. Something almost…threatening. As if he was warning her not to screw up.

 _You're being ridiculous,_ she scolded herself. _He's just worried about making sure his own reputation isn't tarnished by spotty work. You'd do the same._

So instead of letting the comment drop as the Head Boy had clearly meant for it to, Hermione waved her hand dismissively.

"It's just decorations, Riddle," she said. "You could probably do them perfectly in your sleep."

Riddle's lips quirked at the corners as he watched Hermione from the corner of his eyes. For a moment, she thought he might say something more on the subject, but then they had rounded yet another corner where a Hufflepuff and a Ravenclaw were currently in the midst of an impassioned snogging session. Hermione felt her cheeks heat at the intimacy of the position, but Riddle merely cleared his throat, looking almost bored.

"It's well after curfew," he drawled, startling the two students. They pulled apart from each other, trying to discretely wipe saliva from their mouths. "Detention is in order. You'll each serve with your head of house on Friday evening."

"Friday?" the Ravenclaw said incredulously, mouth opening again as if he was ready to launch a volley of complaints.

"Yes, Friday." Hermione interrupted before the boy could even begin to try to dissuade them. "And next time you should think about if sneaking out after curfew is really worth losing your Friday evening."

"Granger, if you'll take Miss Moore back to Hufflepuff, I'll escort Mister Boot to Ravenclaw," Riddle said. "And we'll call it a night?"

Hermione nodded and watched as both Riddle and the Ravenclaw boy disappeared down the darkened hallway. She likely would have stood there for another minute if not for Miss Moore—Miranda, Hermione's mind supplied—did not start stomping off in the direction of Hufflepuff on her own. Hermione quickly trailed after the girl, but her thoughts were still, annoyingly, on Riddle.

Hermione had always been bright and eager to prove her worth. Seventeen years of continuous bullying for her hair or her big front teeth or her know-it-all attitude or her bookishness had done very little to deter that. She'd gotten used to it, had learned to block out Draco Malfoy's whiny insults about her blood, Pansy Parkinson's nasally remarks about her lack of class. Hermione had figured out that they were jealous of her magical talent and intelligence, and so those kinds of comments hadn't bothered her since third year when she had finally steeled her nerve and punched Malfoy in the nose. That had earned her detention, but it had been worth it.

She had wrapped herself in knowledge with renewed vigor. She had practiced spells for hours, pored over every book she could get her hands on. Because if they were going to be jealous and mean, then she would make herself untouchable. Because Draco, or Pansy, or Lavender Brown could be as snide as they wanted, but she was Hermione Granger, the brightest witch of their age.

So she wasn't quite certain why it hurt so much to hear the just-loud-enough whispers in front of her in Charms.

"She just flails her hand around like a dying fish," one of the girls said. "As if that's attractive."

"Everyone knows the only reason she does it is for attention," the other said, turning her head slightly so that she could glance at Hermione from the corner of her eyes. Hermione kept her eyes glued on Flitwick and pretended not to notice. "Because she thinks Riddle will notice her if she's as smart as him. She's been trying to snag him for years."

Hermione felt heat rise to her cheeks. _People don't really think that,_ she told herself. _Do they?_ Her only interest in Tom Riddle was in crushing him academically. She didn't want to prove she was good enough _for_ him, she wanted to prove that she was _better_ than him.

The first girl snorted a little too loudly. "Has she looked in a mirror lately?"

They snickered quietly, but Hermione's anger roiled in her stomach. Insults about her looks were hardly inventive or worth her time, but to think that people might assume she was only _pretending_ to be smart to catch a man, of all things. It was infuriating. Insulting.

Hermione felt her magic fizz around her, pulsing like a current through her veins in response to her emotions. It was almost too easy. They'd been practicing wandless and non-verbal magic this year, and though Hermione had difficulty with the more complicated spells, she could manage some of the basics. Like incendio, for example.

It wasn't hard to act surprised, however, when the bright orange flames leapt up twice as high as Hermione expected on the robes of the girl in front of her. Those in the immediate vicinity shrieked and stumbled to get out of the way as the girl whose robes were currently on fire began tearing off her outer robes. Flitwick was quick to extinguish the flames, though not quick enough to keep the fire from singing off the bottom inch of the girl's hair.

For her part, Hermione was careful to keep a neutral expression as the now-hysterical girl was sent off to the Hospital Wing. She didn't know what had possessed her to actually light another student on fire—and in the middle of class where anyone could have seen. She had just been so angry, she'd barely thought about it. _Stupid, Hermione,_ she told herself. But then, no one seemed to be paying her any mind, and Flitwick was forced to continue the lesson after he realized that there seemed to be no way to prove what had happened.

She did not notice the pair of dark eyes that stayed on her for the rest of the class.

Few people spent their Saturday afternoons in the library, especially when the weather was still pleasant. But Hermione, naturally, was the exception. She liked it best when it was quiet and mostly empty, and even the Ravenclaws usually had better things to do with their weekends than hole up with a dozen books in the back corner of the library. But Harry, Ron, and Ginny were all at Quidditch practice and Gryffindor tower held little appeal without them. Besides, she had less than a year left to access the Hogwarts library and she was going to make use of it.

She had just sat down with a hefty tome on alchemy that was edited by none other than Nicholas Flamel himself when a flash of movement in the restricted section caught her eye. It seemed unlikely for anyone else to be in the library, and it could very well have been a trick of the light, but being Head Girl meant that she was obligated to investigate regardless. She closed her book with a sigh and headed into the stacks. No sooner had she turned the corner did she see none other than Tom Riddle. She couldn't be certain, but she thought, for a moment, it had looked like he had shoved a book into his bag.

 _But that's ridiculous,_ Hermione told herself. _He's Tom Riddle, Head Boy, and Slughorn's favorite. He could check out any book from the restricted section that he wanted. There's no reason to sneak out anything. You're just being paranoid._

He turned at hearing her footsteps. For a split second, there was a strange look on his face that she couldn't quite identify, but it was gone in a flash, replaced by that damned smile. She forced her own smile.

"I should have known it was you," she said with a shake of her head. "Who else would be in the library on a beautiful Saturday?"

"You, apparently," he said with a knowing smirk. "Though I suppose I shouldn't be surprised. It's only your diligence in studying that forces me to the library today."

Somehow, Hermione didn't think that was true. He probably didn't even have to crack open a textbook to keep up with her, the prat. And certainly his trip into the restricted section had little to do with their in-class competition. But fine, she'd let him pretend.

"Someone has to keep you from getting too comfortable at the top," she said, only half-teasing.

She didn't know how she thought he'd react, but it wasn't the sharp bark of laughter that tumbled out of his throat. It was so sudden that it seemed to shock even Riddle himself, and it lasted only for a moment before he reigned in his humor. A smile still tugged at his lips.

"It's a good thing you're around then, Miss Granger," he said, voice pleasantly low. "No one else would do half so good a job."

It was then that she realized just how close they had gotten, though Hermione couldn't recall if she'd been the one to step closer, or if he had. He was less than a pace away, leaning against the bookshelf and looking down at her with this strange, unreadable expression. There was amusement there, but something else. Something unidentifiable that sent a shiver down her spine.

Before Hermione could say anything else, a head of platinum blond hair whipped around the corner in a blur. There was only one person in the entire school with hair that shade, and it was, unfortunately, the only person Hermione absolutely could not stand to be in the same room as.

"Tom, there you are," Draco panted, looking as though he'd just run around half the school looking for the Head Boy. His eyes drifted over to Hermione and his face immediately crumpled as if he'd just smelled two-week old garbage. "Granger. I have a pass, you know."

Hermione resisted the urge to roll her eyes. "I never said you didn't, Malfoy."

Draco continued to scowl at her until Riddle cleared his throat.

"Did you need something?" Riddle asked. "Miss Granger and I were in the middle of a private conversation. It's rude to interrupt."

A befuddled expression came over Draco's face and he looked between Tom and Hermione as his brow wrinkled further. As if he couldn't fathom that the two of them had anything to discuss. Which was probably true, Hermione conceded, considering they hadn't really been talking about anything important. What did Riddle even talk about with his friends? They weren't really the studious type, and Riddle detested Quidditch. _Probably politics and Pureblood family nonsense,_ Hermione concluded.

"You, uh, said to come find you at three o'clock." Draco looked nervously at Tom. "For the study session thing."

 _And wasn't that interesting,_ Hermione thought. Draco had a lot of pride and arrogance, and for him to look at Tom as if the Head Boy had all the power in this situation…well, it had to mean something, didn't it? As far as Hermione knew by her limited understanding of Slytherin politics, Draco should have been a higher rank than Riddle. Malfoy was the sole heir to an extremely prestigious and wealthy family while Riddle had no familial connections to speak of, and on top of that, he was a half-blood. And yet Draco deferred to Riddle. _Why? Because he was Head Boy? Unlikely._

Riddle smiled thinly at Draco, and the blond boy swallowed. "Is it three already? I must've lost track of time. Miss Granger, until next time."

He nodded his head at her while Draco only continue to look on with something between confusion and disgust. Even after they'd gone and Hermione had returned to her book, she couldn't shake the odd feeling that she was missing something. Something important.

Six years of being friends with Harry Potter and Ron Weasley had corrupted her. She knew it had. Because first year Hermione Granger would have never even considered sneaking out after curfew without a good, solid reason. First year Hermione Granger would have been horrified to know that her older self was wandering the halls under a strong disillusionment charm on a night when she didn't have rounds just so she could spy on another student. Specifically so she could spy on the Head Boy, who did have rounds tonight.

She could not justify it. Tom Riddle had been nothing but polite to her, complimentary. He was a model student. But she didn't trust him. No matter how she tried to tell herself she was being ridiculous, no matter how she tried to reason that she had no evidence to suggest that Riddle was up to anything at all, she couldn't shake her gut feeling.

It wasn't hard to find Riddle. Hermione was familiar enough with rounds that she could guess where he'd be at this time of night, and unsurprisingly found him patrolling the halls of the second floor with sixth-year Slytherin prefect, Elias Avery. Getting close enough to listen to their conversation without being discovered was slightly harder, but nothing Hermione couldn't accomplish with a notice-me-not charm and silencing charm on her shoes.

"Did you find it?" Avery asked. "The book, I mean—"

Tom shot the younger boy a dark look. "I know what you mean, Avery." He looked around the hall, making sure no one else was within earshot. Hermione held her breath, but Tom's eyes skimmed right over her.

"And?" Avery asked impatiently.

Riddle, too, had little patience for Avery. He stopped in his tracks and faced the boy coolly. Hermione could not recall a single instance when she had seen Riddle's face so devoid of emotion, so empty. There was none of his usual charm, none of the playfulness he'd shown her in the library. It was like looking into a still lake in the hopes of discovering something beneath the surface, but seeing only your own reflection instead.

"I didn't realize I owed you a detailed explanation of my plans, Avery," Riddle said. On anyone else, the words might have come across as irritated, but Riddle's tone was casual. Hermione almost would have thought he was teasing his friend if she hadn't been able to see Riddle's face. His jaw was clenched, eyes dark and sharp.

"N-no. O-of course n-not," Avery stammered, clearly just as shaken as Hermione felt. "I w-would never presume, my Lord."

Hermione jolted at the title and frowned. _Riddle isn't a lord, though,_ she thought. Or maybe she was wrong. Riddle kept the details of his heritage close to his chest. All she knew was that he was a half-blood and an orphan. But beyond that…hell, he could have been the long lost descendent of the last tsar of Russia for all she knew.

Still, it didn't sit right with her. First Draco's deference, then Avery's fear, and now with the use of a title. Avery was an heir to a lordship in his own right, but everything about his behavior indicated that Riddle was his superior. Hermione couldn't account for it. _Not that I know much about pureblood politics,_ she thought. There were likely quite a few idiosyncrasies that she lacked the cultural understanding for.

Riddle seemed satisfied with Avery's apology. His lips quirked up at the corners, not quite a smile, but it was genuine nonetheless. Hermione was starting to wonder if this was his most genuine self after all. The fake smiles, the polite, perfect Head Boy act…what if it was just that? An act. And this…this empty, blank, terrifying nothingness was the real Riddle?

 _Or maybe he's just as fed up with Avery as you are, and his resting bitch face is better,_ she thought. _Maybe you should stop looking for reasons to mistrust Riddle._

Still, those thoughts didn't stop her from following them as they continued walking.

"To answer your question," Riddle drawled, seemingly back to his normal self. Mostly. "Everything will be ready in time for Samhain."

"And is it everything you hoped for, my lord?" Avery asked, practically bouncing on the balls of his feet. The younger boy, who had only a moment ago been all but cowering beneath Riddle's gaze, now was alight with barely restrained excitement. Whatever they were talking about, it was apparently highly anticipated.

Riddle's smirk was sharp as a knife. "It exceeds expectations."

And just like that, the conversation was clearly over. Riddle had moved on to asking Avery about his arithmancy test scores, and Hermione decided that there was nothing more to be gained from following them. She returned to her own dorm room, mind turning over everything that she'd heard.

A book, Samhain, and something will be ready. The obvious answer was a ritual of some sort, but what kind, she didn't know. And would Riddle really be stupid enough to do something like that on school grounds? _Unless he's already planned for that, which of course he has,_ Hermione thought. So Riddle and his…friends (could she really call them that when it was becoming clear that Riddle was above them) were up to something. She had been right, after all.

All that was left was to find out what they were doing.

The Great Hall was buzzing as it always did on holidays. Every meal at Hogwarts was incredible, but the Halloween feast in particular was exceptional. The atmosphere was half of it: floating jack-o-lanterns, black silk draping the walls, and even a skeleton dressed like Albus Dumbledore seated in the headmaster's chair (courtesy of some would-be-pranksters who'd heard the legends of Fred and George Weasley, no doubt). Hermione had put in several hours of work herself, and yet she found she couldn't quite enjoy it.

All she could think about was Riddle and Avery talking, and that book he'd taken from the restricted section. The more she thought about it, the more certain she was that she hadn't imagined him smuggling a book out of the library after all. She had tried and failed to come up with a reason for what she'd seen that didn't involve Riddle having some dark, nefarious plan. She had half expected him to not be at the feast, but no, there he was at the Slytherin table. He was just as magnetically handsome as ever, sitting at the far end of the table with the other seventh years. Specifically, those boys that she had seen with him in the library.

They were up to something, and unfortunately, Hermione had to admit that it was the perfect night for it. The moon was full, it was Samhain, and the air itself seemed to shimmer with unspent magic. But she had nothing to go on. A week of observing Riddle and his friends had gotten her no new information, and research on Samhain had yielded minimal results.

 _It might be nothing,_ a small part of her brain whispered. _Maybe they just want to practice a traditional Samhain ritual. They'd have to hide it since it is technically illegal, but…well, there's nothing actually wrong with it. Nothing truly terrible._

But as the evening progressed, she couldn't stop the niggling thought in her mind that something just wasn't right. Not even dessert—little cauldron cakes and treacle tarts and piles of candy—could distract her. Not Ron reenacting the incident of him vomiting up slugs with the candied gummy worms for all the delighted first years. Not Ginny and Harry who had somehow managed to make the one of the floating jack-o-lanterns talk.

Riddle was standing, his little group quickly following suit, and they strode out of the hall together. If Hermione hadn't been watching Riddle, she might not have even noticed that they left. Nobody else seemed to. Without fully realizing what she was doing, Hermione stood abruptly.

"'Mione?" Harry asked, a worried crease between his brow.

"Just feeling a little sick all of a sudden," she mumbled. "I think I'm going to go lie down in the dorms."

"Do you want someone to walk with you?" he asked, although Hermione could tell that he was reluctant to leave the festivities. She shook her head.

"I'll be fine. See you later."

The logical part of her brain was screaming at her that it was stupid to go after Riddle and all of his friends on her own. She should tell Harry and Ron what she was doing, but how could she explain that she had witnessed suspicious behavior and kept it to herself? She wasn't sure why she hadn't told anyone. Probably because she was still trying to convince herself that it was nothing. Probably because she knew that Harry and Ron would immediately want to do something rash just because Riddle and his gang were Slytherins.

 _But aren't you doing something rash by following them?_

She ignored her own thoughts and hurried after them, keeping far enough away that she could only see the tail end of their robes as they turned the corners. It didn't take her long to realize that they were heading out of the castle and onto the grounds where it would be harder for her to follow them undetected. Not for the first time, she wished she had Harry's invisibility cloak.

 _Maybe you could've borrowed it if you'd actually told them what you were doing,_ a snide voice in her head said. She ignored it and cast another disillusionment charm over herself before following them out onto the grounds. They were still some distance ahead of her, but the moonlight was bright enough that she could see them: Riddle's tall figure at the head of the group, a shock of platinum hair where Malfoy stood, and two other figures. Avery and Lestrange, if Hermione had to guess. And they were headed into the Forbidden Forest.

 _I must be suicidal,_ she thought, hurrying to catch up so that she didn't lose them among the trees. Her own experience with the Forbidden Forest was decidedly unpleasant. They had never found out what was killing unicorns in her first year when she'd gone there for detention, and she was pretty sure that Acromantula colony that she, Ron, and Harry had found in their second year was still there. Not to mention that the centaurs weren't too fond of wizards encroaching on their territory, and Hermione wasn't 100% sure that there wasn't a werewolf pack somewhere in there too.

Luckily, they didn't go in too deep, just enough that the castle was no longer visible through the trees. Hermione stopped, hiding behind a tree as she watched Riddle take his place in the center of a large circle directly in front of a stone slab. He pulled a book out from his robes and placed it open in front of him. Malfoy, Avery, and Lestrange disappeared further into the forest while Riddle sprinkled sea salt in the circle around the stone, muttering some incantation under his breath. A moment later, the other three boys returned, this time with a bound centaur floating behind them.

Hermione clamped her hand over her mouth to prevent her gasp from being heard. So her suspicions were confirmed; this was not an ordinary Samhain ritual. The centaur – who was struggling against his bindings – was deposited unceremoniously on the stone slab. Malfoy, Avery, and Lestrange were careful to stay outside the ritual circle. Riddle began chanting from the book, but Hermione couldn't hear the words, only the rhythmic quality of them. There was something almost hypnotic about the way Riddle spoke, though perhaps that was in part due to the magic rolling off of him. It made the air heavy, so much so that she could hardly breathe. She knew she should get out of there, leave before she was discovered, but her feet felt rooted to the spot. She wanted to know what he was doing, and the only way to do that was to stay.

Riddle drew his wand and with elegant movements, he crafted runes in the air. The first, othila, looked almost like a crudely drawn fish. It glowed silver, hanging in the air over the centaur's head. Hermione searched her brain for the meaning, certain that it would help her understand what he was doing. _Separation or acquisition,_ her mind supplied, providing an image of her runes textbook. Just as she thought it, the centaur convulsed on the stone slab and screeched horribly. The sound alone made Hermione want to vomit, for it was so clearly the sound of a creature in pain.

She wanted nothing more than to stop Riddle, but with his bodyguards, she knew she wouldn't be able to get close enough. Dueling wasn't her strength, and against Malfoy, Avery, and Lestrange, she knew she would lose very quickly. Given that she couldn't win, she'd only be revealing herself and making herself a possible target as well. And now that she was seeing just what Riddle was capable of, Hermione was very sure that the last place she wanted to be was on the wrong end of his wand.

The next rune appeared, ehwaz, in the shape of a sharp "M." _Transition and movement,_ Hermione recognized, and she watched as the convulsing stopped. A small orb of light tugged away from the centaur's body, not unlike the glimpse she'd once seen of a dementor successfully removing the soul from a human body, and drifted towards Riddle with a serenity that was entirely at odds with the whole situation. _He separated something from the centaur,_ Hermione realized, bile rising in her throat. _And he's sending it to himself._

Her suspicion was confirmed in the next moment when Riddle drew the rune gebo above the centaur's head. It looked like nothing but a simple "x" in the air, but Hermione knew what it meant: _gift or union._ Whatever Riddle had stolen from the centaur, he was now merging it with his own body and magic. The orb of light went straight through his chest, and though the force of it was enough to bring Riddle to his knees—causing a small commotion from the other three boys just outside the circle—Riddle never once faltered in his chanting.

He hauled himself to his feet with gritted teeth and drew the next rune, dagaz, shaped like an hourglass turned on its side. _Transformation_ was the most common reading, and Hermione could tell enough of the ceremony by now that this was what Riddle had intended. A silvery light encased the dark-haired boy for a moment before dissipating. At first, Hermione thought that he must have failed because Riddle looked no different from before. But he seemed satisfied enough to continue on.

One final rune was drawn above the centaur. Sowilu, the symbol of wholeness. Hermione had always thought of it as one of the purest runes, but now she watched Riddle twist it for his own evil. If her assumptions about the ritual were correct, this final rune would allow for the seamless absorption of whatever Riddle had stolen. It would grant him power, the literal _life force_ of the centaur, if the ritual was strong enough.

With a flash of light and deafening crack that rattled in Hermione's head, the ritual was over. The stone slab that the centaur was resting on had shattered. Riddle was on his knees again, but this time, his friends rushed forward offering their aid. But they had missed what Hermione had not; they had mistaken Riddle for weak in this moment. But Hermione could feel the power radiating off of him. She could feel the magic rolling off of the dark-haired boy in nearly-oppressive waves.

She needed to leave. _Now._ And perhaps she would have, if not for the fact that at that exact moment, a horrible wail left the centaur. He was still alive somehow, though deeply pained. _I could still save him,_ Hermione thought, though she didn't know how. Perhaps Riddle would just leave the centaur to die, and if she waited, she could untie the poor thing, heal it to the best of her abilities. She could—

She could not do any of those things because Riddle waved off the other boys, hauled himself to his feet one more time, rolling his shoulders. He didn't look like someone who had been floored by a magical ritual. He looked like he had just woken up, well-rested, from a full eight hours of sleep. And just as the centaur opened his mouth to scream again, Riddle flicked his wand lazily and a bright jet of green light hit the poor creature squarely in the chest.

Hermione's stomach dropped, her knees close to buckling beneath her. Tom Riddle—the esteemed Head Boy, the darling of Hogwarts, the perfect gentleman—had just used an unforgiveable. And not any unforgiveable, but the killing curse. Nonverbally, with such casual disregard that Hermione almost didn't believe her own eyes. Because only psychopaths were that apathetic, and Tom Riddle…Tom Riddle…

 _Is a psychopath,_ Hermione realized. _And you, you stupid, self-righteous, careless moron. You followed him out into the Forbidden Forest. Alone._

If she'd left during the ritual, she might have been able to make it out unnoticed, but now she'd have to wait for the boys to leave first. They'd have to walk right past her, and she prayed to Merlin that magic would be on her side tonight. That luck might take pity on her and let her escape unscathed.

"You can come out now, Granger," Tom called, his voice soft and deceptively calm. "I do hope you enjoyed the show."

Hermione gripped her wand. She couldn't take him in a duel. Tom was fast and he never held back. Or at least, she thought he hadn't, but clearly he could cast the unforgiveables and who knew what other dark curses. All this time she thought she was seeing right through him, but still she underestimated him. _Maybe he's underestimated me too._

She stepped out from her hiding place, wand raised. Malfoy, Avery, and Lestrange were all on edge, all looked ready to strike at a moment's notice, but Riddle just stood there, smug and smiling. She wanted to hex the smirk right off his face. _Patience, Hermione._

"Ah, there you are." Riddle had no right to look as pleased as he did. She would have thought he'd be angry that she'd crashed his little ritual, angry that someone had seen him at his worst. _Or at least, what you hope is his worst._ "No need to be shy, Granger."

"What did you do?" she demanded, her eyes flickering briefly to the dead centaur, but her wand never wavered from where it was aimed at Riddle.

"Always so curious," the dark-haired boy mused. "But you waste time asking questions you already know the answer to."

Hermione grit her teeth. "Fine. What did you take, then?"

Riddles eyes flashed, his smile widening. _Even Lavender Brown wouldn't find him so charming now,_ Hermione thought. Riddle was enjoying this too much: the ritual, the murder, the game he was playing with Hermione. This was the most alive she'd ever seen him, and it was sickening.

"Clever, clever girl." He jerked his head at the other three boys, and Hermione's eyes darted to them for just long enough to see their confused expressions. "They still don't understand, you know. Avery and Lestrange are rubbish with runes, and Draco lacks the ingenuity to piece it together, but _you_ —"

And the way he said that, the way he looked at her in that moment, was almost reverent. Like he was amazed by her, in awe of her. Hermione felt her skin crawl. Maybe before tonight, she would have melted a little under his gaze if he had looked at her like that. But now she saw him for all that he was: a vile, disgusting, uncaring killer. Everything good and admirable in him was a carefully crafted lie.

" _You_ figured it out at a glance. I knew you would understand. It took me weeks to find the book, and another week to make sure you were there in the library when I took it." Riddle still hadn't drawn his wand on her, but he was advancing. For every one of his steps towards her, Hermione stepped back, but there was only so much farther she could go before she would inevitably be trapped.

"But I didn't," Hermione protested. "See you take the book, that is."

Riddle shrugged. "You saw enough to make you suspicious. You see, for all of your precious Gryffindor morality, you do so like to stick your nose where it doesn't fucking belong. I counted on that."

"You knew," she breathed, the realization of the depth of Riddle's manipulations hitting her like a train. "You knew I was there in the hallway that night."

"You're really quite clever," he said, stepping forward again. Hermione's back hit a tree and she looked around, searching for a way out, but he was too close now. She was trapped. "I knew if I let enough slip, you would be watching, waiting."

There was less than a foot of distance between them now. It was far too close for Hermione's comfort, and yet Riddle was still leaning in, bracing his arms on the tree behind her, forming a cage around her. Without thinking, she jabbed her wand up, pressing in into the soft of Riddle's neck. And again, he surprised her by laughing.

"We're not so different, you and I," he said calmly, as if he didn't have a weapon pressed to his throat. His hand reached up, and he lightly trailed a finger down her wand. She could feel the tendrils of his magic reaching out to her, how her own magic almost ached to seek his out in turn. "That's why I want you."

Her eyes went wide, nose involuntarily wrinkling at the thought. As if she would ever willingly let him put his hands on her after seeing what he'd done, what he was capable of. As if she would want him.

Riddle rolled his eyes. "Not like that, you ridiculous girl. Your mind and your magic are of value to me."

That was only slightly comforting. The idea of Riddle wanting her physically was certainly revolting, but admiring her for her mind, for her abilities…what did that say about her? What about her reminded him of himself? She wanted to know so she could purge it from her being.

"Although…I suppose I can see the appeal," he murmured almost to himself as he tucked a strand of her wild hair away from her face. Hermione was on the verge of asking him what the hell did he think he was doing when Riddle suddenly bent down and covered her mouth with his. For a moment, she was too confused to do anything. All she could process was that his mouth was warm, his lips soft against hers, but demanding. She didn't kiss him back, but that didn't seem to matter.

And then, though she seemed to have forgotten her wand, she remembered with strange clarity being nine years old, sitting in the kitchen with her mother. They were sharing a grilled cheese, and Hermione had mentioned off-hand that a boy on the playground wouldn't stop tugging on her hair.

Her mother had gotten very serious and said, "If anyone touches you when you don't want them to, and they won't stop when you tell them to, then you hit them, Hermione. As hard as you can. I don't care if it's the boy on the playground, or if it's a girl in your class, or if it's an adult. Nobody else has a right to your body."

She made a fist just like her mother had taught her and punched with as much force as she could muster. Right in the gut. Riddle stumbled back, doubled over and gasping for air. The other three boys were quick to train their wands on Hermione, but hers was aimed at Tom. Using the sleeve of her robe, Hermione wiped the saliva from her mouth.

"What. The. Fuck," she spat. She glared at him as he pulled himself upright. The look on his face was murderous, but Hermione supposed that hers was as well. "What kind of idiocy would possess you to think I would want you to touch me? Especially after what you've just done?"

"I should have known your delicate sensibilities would get in the way," Riddle growled, pointing his own wand at her. He schooled his features, though his nostrils still flared in irritation. "No matter. In time, you'll learn to be free of them."

"Like hell I will."

"Draco," Riddle called, ignoring Hermione entirely. "We'll require your assistance for an unbreakable vow."

Hermione jerked her head between Riddle and Malfoy. "If you think I'll agree to an unbreakable vow—"

"You will," Tom said plainly. He leveled his wand at her head. "Because it's either that, or I obliviate you. And I've put in so much work to ensure you were here to see this, it would be a waste."

"I don't give a flying fuck—"

Riddle's smile turned sharp. "And because if I obliviate you, I can't promise I'll only take this memory from that pretty little head of yours."

Hermione froze. She had no doubt that if he got into her head, he'd take whatever he wanted. He could destroy her, vanish her entire childhood, or erase key parts of herself. He could shape her into whatever he wanted, and though once she might have doubted whether or not he had the skill to do so, she now knew better.

"Fine," she said. "But I want something in return for my silence, Riddle."

His eyes shone in the darkness of the forest. "Which is?"

"That you won't harm me, nor will you have anyone harm me on your behalf."

Riddle laughed again. "Not going to bargain for your friends too? I'm almost disappointed."

"You would never agree to that," she pointed out. Riddle narrowed his eyes, though not in anger. It was more like he was observing her, trying to figure her out.

"No, I wouldn't have," he agreed after a moment. "But I'll give you what you ask."

Draco stood between them as Hermione and Tom clasped their hands together, and waved his wand so that a golden strand of magic tethered them together.

"I, Tom Marvolo Riddle, do swear to never harm Hermione Granger nor have others harm her on my behalf, so long as she does not reveal the plans or actions taken by me and the Knights of Walpurgis without my express permission."

Hermione glared at him. This was not what she had agreed to when she had consented to the unbreakable vow, but she should have expected that Tom would try to get more than he was giving. She was on the verge of protesting this sudden change in wording when a voice from the back of her mind spoke up. _This is your chance to get on the inside. Find out what the Knights of Walpurgis are. Find out what Tom is really up to. You can find a way to work around the wording of the vow later._

"I, Hermione Jean Granger, do swear to never reveal the plans or actions taken by Tom Riddle and the Knights of Walpurgis without his express permission, so long as he does not attempt to harm me or have others harm me on his behalf."

The magic briefly tightened around them before it dissipated into thin air. Draco looked warily between the two people in front of him. Tom grinned.

"Welcome to the Knights of Walpurgis, Hermione," he said.

"I didn't join your little group," she started to say, but Tom's eyes misted over. His smile only grew wider, and for a second, Hermione was concerned that the ritual he'd done had somehow made him even more insane. But then his eyes cleared and his grip tightened on her wrist.

"You asked what I took from the centaur," he all but whispered. Hermione couldn't help but find herself drawn in. "I'll give you a hint. The ritual lets you take a creature's natural abilities. What would a centaur have that I'd want?"

Hermione swallowed back the panic rising in her throat. "Divination."

"Good girl." His thumb circled her pulse on her wrist. He smiled again and released her. "Maybe you're not one of mine yet. But you will be."

 _He could be lying,_ she told herself. _But what if he's not?_

With a flick of his wand, he vanished all the evidence of his ritual. "We'd better get back before we're missed."

Hermione followed him numbly back to the castle. With Riddle's newly acquired skill of divination, she'd never be able to catch him off guard. He would know if she was going to betray him. She'd thought she'd been so clever. She'd thought she could beat him, somehow.

"Good night, Hermione," Riddle whispered very close to her ear, his warm breath fanning across her cheek. "Sleep well."

As she watched him retreating to the Slytherin dungeons, she couldn't help feeling that she'd made a terrible, terrible mistake.

-Author's Note-

Hi all! This is part of my October Spook-Fest that I'm doing over on ao3, but I thought I'd go ahead and post it here as well! These are mostly going to be one-shots, though I may return to any of them for a follow up chapter at a later time! There are probably a few spelling/grammar errors because I just crank out a fic and post without editing, so sorry for any confusion!

ALSO I'm now on tumblr as **officialsporkintheroad** if you want to talk to me, have an idea for a Tomione fic that I might be persuaded to write, or if you want to see aesthetic/moodboards and mock book covers for my stories!


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